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pseries/iommu: Ensure TCEs are cleared with non-huge DDW

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There are now two kinds of DMA windows that might be presented by
PowerVM DDW support -- huge windows (that can map all of system memory
regardless of the LPAR configuration) and non-huge windows (which
can't). They are implemented slightly differently in PowerVM, and thus
have different characteristics. The most obvious is that slot isolate
doesn't clear the TCEs/window for us with non-huge windows. Thus, when a
DLPAR operation occurs on a slot using a non-huge window, TCEs are still
present (the notifier chain doesn't currently remove them explicitly)
and the DLPAR fails. Fix this by calling remove_ddw() first, which will
unmap the DDW TCEs.

Note: a corresponding change to drmgr is needed to actually successfully
DLPAR, such that the device-tree update (which causes the notifier chain
to fire) occurs before slot isolate.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nishanth Aravamudan 2013-01-18 09:17:36 +00:00 committed by Benjamin Herrenschmidt
parent 22b382985a
commit 71cf1def1a
1 changed files with 1 additions and 10 deletions
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11
arch/powerpc/platforms/pseries/iommu.c
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@ -1296,6 +1296,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
switch (action) {
case OF_RECONFIG_DETACH_NODE:
remove_ddw(np);
if (pci && pci->iommu_table)
iommu_free_table(pci->iommu_table, np->full_name);
@ -1308,16 +1309,6 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
}
}
spin_unlock(&direct_window_list_lock);
/*
* Because the notifier runs after isolation of the
* slot, we are guaranteed any DMA window has already
* been revoked and the TCEs have been marked invalid,
* so we don't need a call to remove_ddw(np). However,
* if an additional notifier action is added before the
* isolate call, we should update this code for
* completeness with such a call.
*/
break;
default:
err = NOTIFY_DONE;